FAQ's about research practice, use of statistics in research, surveys, use of SPSS and questionnaire design.

What sample size do I need for my survey results to be valid?
The easy answer is that you need to use a formula for your specific situation. To decide which formula to use you should give some more information.
If you have no information you can use the following table to determine the sample size (N = population size; S = sample size)





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Correlation & causation
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